A filling arrangement for filling and emptying an anesthetic vaporizer with anesthetic liquid via a supply vessel connected thereto is known from U.S. Pat. No. 4,867,212. The filling arrangement includes a movable tubular conducting member which at one end is connected to the supply vessel and, at the other end, the conducting member has an index connecting piece for connecting into the anesthetic vaporizer. The tubular conducting member has a ventilating channel separate from the filling channel. Both channels extend from the supply vessel to the connecting piece as coaxial lines.
For filling, the connecting piece of the tubular conduit unit is engaged with the anesthetic vaporizer and the supply vessel is lifted. After a switch-over valve on the anesthetic vaporizer has been actuated, the anesthetic liquid flows through the filling channel into the tank of the anesthetic vaporizer because of the hydrostatic pressure, while at the same time, the gas volume displaced from the tank of the anesthetic vaporizer reaches the supply vessel via the venting channel. The filling channel and venting channel have the function of communicating tubes between the supply vessel and the tank of the anesthetic vaporizer.
After ending the filling operation, the supply vessel is lowered and the switch-over valve on the anesthetic vaporizer is again closed. A rotatable joint is provided within the conduit assembly of the tubular conduit piece for lifting and lowering the supply vessel. The supply vessel is pivoted about the rotatable joint. A blocking device is integrated into the rotatable joint which closes the filling channel and the venting channel when the supply vessel is lowered after filling.
The known arrangement has the disadvantage that the blocking device is actuated by the lifting and lowering of the supply vessel independently of what vapor pressure has formed within the supply vessel by the anesthetic liquid. If the supply vessel contains an anesthetic liquid which boils at a low temperature, then it can be impossible to fill the anesthetic vaporizer even at usual room temperatures because of bubble formation. Furthermore, if the blocking device is inadvertently opened such as by rotating the tubular conduit unit, the vaporous part of the anesthetic liquid disposed in the supply vessel can escape to the ambient and the anesthetic liquid begins to boil because of the drop in pressure. After a short time, the entire supply of anesthetic liquid can be vaporized.
German patent publication DE-AS 1,657,174 (U.S. patent application Ser. No. 616,961, filed Feb. 17, 1967) discloses a further filling arrangement for connecting a supply vessel to an anesthetic vaporizer. A coupling system with valves is provided at the connecting location between the anesthetic vaporizer and the supply vessel. The valves are opened by means of coupling pins during the coupling operation. When filling, the anesthetic liquid flows under the force of gravity through a filling channel into the tank of the anesthetic vaporizer and the base chamber of the supply vessel turned upside down is ventilated via a ventilating channel.
It is disadvantageous in this arrangement that the filling operation is affected by anesthetic liquids having a low boiling point since the switching of the filling operation is influenced only by the correct alignment of corresponding coupling pins but is not influenced by the temperature of the anesthetic liquid.